As pointed out in my earlier application, which is hereby incorporated in its entirety by reference, a rake is a commonly used tool in agriculture, horticulture, soil preparation, and ground maintenance and for other purposes in which an array of tines is displaced in a combing action generally along the ground. Generally speaking, the tines of the rake are fixed with respect to a carrier for the tines although there are manual rakes known which allow the spacing of the tines to be adjusted by, for example, shifting of the tines with respect to the support to move them closer together or further apart.
However, both manual rakes and various forms of soil tilling implements using rake principles, such as spike harrows, fix the tines with respect to the support at least for a given soil preparation operation so that they are in effect fixed-tine implements.
The soil preparation efficiency with fixed-tine implements is not great and the aforementioned copending application points out that the efficiency of soil preparation can be greatly improved, that the versatility of an implement with respect to raking functions may likewise be enhanced and the soil preparation utilizing a rake action can be simplified if the rake is provided with self-orienting tines, pivotally generally about upright axes and designed to selectively present broad and narrow sides to the soil to be moved or acted upon.
Specifically that application discloses a manual rake having a transverse member (support) adapted to be displaced substantially parallel to the ground and having a multiplicity of spaced-apart tines projecting downwardly from this support, and means for pivotally mounting each tine about a respective axis transverse to the support and representing a longitudinal axis of the tine.
Advantageously, each tine is provided with a groundengaging portion which is eccentric with respect to its axis so that when the rake is drawn in one direction along the ground, torsional force (torque) is applied to each tine tending to rotate it in one direction or sense whereas when the rake is displaced in the opposite direction along the ground, each tine swings into a second position which can present a broad side to the ground.
Stop means is provided on the support for immobilizing tines in each of these limiting positions so that when the tines are retained in one of these positions, they may assume an on-edge orientation with respect to the direction of displacement and thereby slice through the soil, whereas when swung in the opposite sense and there held, the tines may present broad surfaces to the direction of displacement and thereby displace a large amount of material.
The alternation of groove cutting and broad-side displacement has been found to be energetically efficient because the broad-side displacement, which involves most work, is easier and less energy consuming after the grooves have been previously formed by the slicing action.
Advantageously, the tines described in that application are flat blades having free pointed ends offset from the axes of the blades, the blades having laterally projecting tabs which engage pins depending from the support and forming the stops.
This manual rake is especially effective when manipulated with a back-and-forth motion so that the support moves horizontally, perpendicular to itself, forward and back to pulverize and work the ground.